Percussion device for firearms



Feb. 24, 1970 F. A.- DONNER 3,

PERCUSSION DEVICE FOR FIREARMS- Filed April 11, 1968 2 Sheets-Sheet 1 TryS.

Feb. 2%, 1970 F. A. DONNER 3,495,323

PERCUSSION DEVICE FOR FIREARMS Filed April 11, 1968 2 Sheets-Sheet z 3,496,828 PERCUSSION DEVICE FOR FIREARMS Fredric Arno Donner, Rahapakantu 1, Helsinki, Finland Filed Apr. 11, 1968, Ser. No. 720,681 Claims priority, application France, Apr. 20, 1967,

hit. or. F41r 1/06 US. Cl. 89-416 1 Claim ABSTRACT OF THE DISCLOSURE The striker for a firearm such as a mortar consists of a rod supported for axial sliding movement in a passage which includes a valve seat facing the projectile-receiving chamber of the firearm, and the striker rod is provided with a sealing valve which is applied against the valve seat by return means associated with the striker rod, the valve and valve seat providing a seal before the process of combustion of powder gives rise to high gas ressure.

BACKGROUND OF THE INVENTION Field of the invention The invention relates to firing mechanism for firearms, particularly firearms such as mortars.

Description of the prior art The construction of a firearm striker presents no particular ditficulty in the case of the firing of a projectile by means of a firing charge enclosed in a cartridge case. The latter in fact, by bearing against the walls of the projectile-receiving chamber, confines the hot gases produced by the combustion of the powder and any leakage, after partial cooling and expansion, tends to seek a passage through the striker. In this case, known mechanisms offer a degree of safety which is generally sufficient.

The same is not true when, as is usually the case with mortars, the firing charge and the gases which it produces are directly in contact with the walls of the projectilereceiving chamber, including the bottom of the latter, and

' with the orifice of the striker.

In this case various expedients are adopted, generally utilising the pressure of the gases, to provide a seal against the burning gases around the striker rod, by gripping around the latter. Such sealing devices, which require extreme precision in manufacture, however, entail serious disadvantages.

In the event of the accidental malfunctioning of the sealing device, the striker rod is in fact corroded by the burning gases, tightness can no longer be obtained, corrosion is accelerated, and the rod is rapidly destroyed. Another disadvantage is that the gripping around the rod may occur in the percussion position and the rod may be wedged in that position through the action of condensed or deposited combustion residues. When the next shot is fired, the percussion takes place as soon as loading is effected, thus giving rise to serious, uncontrollable danger of premature firing, or else percussion does not take place if wedging occurs in the retracted position of the striker, thus necessitating delicate and dangerous operations for the unloading of the weapon.

Another disadvantage of known devices arises from the fact that on the firing of the shot, even with Weapons having practically no recoil such as mortars, a certain recoil of slight amplitude nevertheless occurs, and this recoil has an acceleration of very high value because of the lightness of the barrel. This acceleration may attain from 2000 to 3000g, and in its relative movement the striker rod is thrown forwards, thus bringing about a further percussion and increasing the possibility of wedg- 3,496,828 Patented Feb. 24, 1970 ing in its forward position, with the dangers involved thereby.

It is an object of the present invention to provide a firearm percussion mechanism enabling the abovementioned disadvantages to be obviated.

SUMMARY According to the invention there is provided a percussion device for firearms, comprising a projectile receiving chamber having associated therewith a striker rod and a striker formed by a rod which strikes against a pzimer, striking mechanism including a hammer, wherein the striker rod is slidable axially and freely in a passage provided through a wall of the projectile-receiving chamber and carries a sealing valve for co-operation with a seat formed around said passage and facing the interior of the chamber, and wherein return means co-operates with the striker rod to hold the sealing valve against said seat.

The force applied by the return means is designed to effect the return of the valve to its Seat in a predetermined time, which is variable in accordance with the various applications of the invention and Which makes it possible to provide a seal before the process of combustion of the powder gives rise to high gas pressure.

Any phenomenon of double percussion is made impossible, which is also true of the rebounding of the valve on its seat, because of the combined action of the tension of the springs, the small weight of the rod, and the gas pressure, which contributes towards maintaining the valve against its seat.

Moreover, wedging cannot occur, because the rod slides freely in its passage and is protected against burning gases.

In one embodiment of the invention, the hammer is so arranged as not to hinder the return of the valve to its seat, and for that purpose is provided with return means returning it to the neutral position.

According to various alternatives, the hammer is returned to the starting position by a spring of determined force, which may or may not be assisted by the effect of the rebound of the hammer at the end of the percussion movement, or by a positive drive.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is an axial section of a striker according to the invention, with a percussion hammer,

FIG. 2 is a partial view illustrating a positively driven hammer in an intermediate position, and

FIGS. 3 and 4 illustrate the hammer of FIG. 2, in the percussion and return positions.

DESCRIPTION OF THE PREFERRED EMBODIMENT Referring to the drawings, FIG. 1 shows in partial section a firearm barrel 1 having a bottom 2 provided with an internal boss 3. The boss 3 is extended towards the interior of the projectile-receiving chamber 1' of the barrel by means of a tube 4 divided by an intermediate partition 5 into two compartments, namely the front and rear compartments designated by 6 and 7 respectively. At its front end the front compartment 6 is closed by a plate 8 held in position by means of a threaded cap 9 screwed on the tube 4.

The cap 9, plate 8, and partition 5 have coaxial holes in which a striker rod 10 is slidably mounted. The striker rod 10 has an enlarged portion 11 forming a sealing valve, and round its hole for the passage of the rod 10 the plate 8 has a corresponding valve seat 12 which faces towards the chamber 1'.

The rod 10 also carries a collar 13 opposite the front face of the partition 5. A system of springs 14, composed of cup springs or other spring elements, is disposed or compressed between the front face of the collar 13 and the rear face of the closure plate 8, and serves to maintain valve 11 against or to return it into seating relation with its seat 12.

According to numerical example given purely by Way of indication, the weight of the striker rod, including its enlarged portion forming the valve, and added to an adequate fraction of the weight of the washers forming a spring, is of the order of grams and the pressure of the springs is designed so that the valve is returned to its seat in a time of from 2 to 3 milliseconds as a maximum, counting from the moment of percussion, the total movement of the moving parts being about 2.5 mm.

In FIG. 1, the striking mechanism is formed of a heavy part or hammer 22 suitably actuated, for example by means of a spring previously loaded and abruptly freed.

The hammer 22 encounters the rod of the striker 10 and approximately at the same moment encounters the resistance of a powerful spring 15. The hammer has sufiicient energy to compress the spring plus the return spring 14 for the rod and to effect the percussion, after which at the end of its movement it strikes against the bottom of its housing, constituted by the rear face 16 of the partition 5.

In one application, the spring has a force such that it effects the return of the hammer in a time at most equal to the time required to effect the closing of the striker valve. Thus the time during which the valve remains open is not influenced by the striking mechanism.

In another application, the striking mechanism itself determines, through its return, the moment of closing of the valve, the spring 15 being designed to effect this return before the hot gases reach a high pressure.

In a variant of this last application, the hammer return spring has a more prolonged action and the rebound of the hammer at the end of its movement is used to free the valve closing movement.

According to another alternative, (which is illustrated in FIGS. 2 to 4, the movements of the hammer 22 have a positive drive by means of an eccentric 17, and the rod 10 carries a rear tip 18 which is of greater cross-section than that of the rod 10 and which is in a freely slidable chamber 19 formed in front of the hammer 22. FIGS.

2, 3 and 4 respectively show the hammer in the middle position, at the end of the percussion movement, and at the end of the return movement.

As can be seen from FIGS. 3 and 4, percussion is eifected through contact of the rear face 20 of the chamber 19 with the tip 18, and the rod is also returned positively through the contact of the tip 18 with the front face 21 of the chamber 19. A complete forward and return movement of the rod and hammer corresponds to a movement of one revolution of the eccentric 17, which is effected abruptly under the action of a spring.

The positive return drive makes it possible to ensure the return to the rear of the striker point, to enable it to retract into the cap 9 out of the chamber 1, and to eliminate the danger of premature percussion on the next loading. Nevertheless, the return movement of the hammer 22 is not suflicient to bring the valve back against its seat, and the return movement of the valve is completed freely under the action of the springs 14.

I claim:

1. A percussion device for mortars having a projectile receiving chamber comprising a compartment defining structure with a tubular wall and two end walls, a striker rod, striking mechanism including a hammer, wherein the striker rod is slidable axially and freely through coaxial holes formed respectively in said end walls and carries a sealing valve for cooperation with a seat formed around one of said holes for shutting off said compartment from said chamber, and return means located within said compartment around said striker rod to hold the sealing valve against said seat.

References Cited UNITED STATES PATENTS 2,477,253 7/1949 Jasse 89--27 X 2,714,836 8/1955 Jasse 8927 3,355,989 12/1967 Kruze 89-26 X SAMUEL FEINBERG, Primary Examiner S. C. BENTLEY, Assistant Examiner s. :1. X.R, 

